I wouldn't mind seeing something with the same form factor as the GPD Win3, but using a relatively low-power processor for better battery life. I suppose that wouldn't drop down the price enough to make it desirable to most of the target market though.
If you don't mind the lack of gaming controls, they have some Pentium N6000-based models. The P2 Max (2022) with this claims 8 hours continuous 1080p playback.
Still expensive though - would be great to see a more terminal-focused version with a lower power CPU and screen for a few hundred, and presumably a battery life measured in days.
The Micro PC seems about right though with a 6in screen.
Apparently not for sale new anymore, and it seemed expensive when it was.